cat명령어로 특정파일의 내용확인 시에 두개이상의 빈행이 연속될 때에 한행만 출력하기

[root@su250 ~]# cat textfile

Based upon the NCSA server

configuration files

originally by Rob McCool.

This is the main Apache server

configuration file.

It contains the configuration directives

that give the server

its instructions.

[root@su250 ~]#
[root@su250 ~]# cat -s textfile

Based upon the NCSA server

configuration files

originally by Rob McCool.

This is the main Apache server

configuration file.

It contains the configuration directives

that give the server

its instructions.

[root@su250 ~]#
[root@su250 ~]# cat -sn textfile

     1  Based upon the NCSA server

     2  configuration files

     3  originally by Rob McCool.

     4

     5  This is the main Apache server

     6  configuration file.

     7

     8  It contains the configuration directives

     9  that give the server

    10  its instructions.

[root@su250 ~]#